Electric welding.



0. A. KENYON.

ELECTRIC WELDING.

APPLICATION FILED .IIINE 28.19IeA @Nounou describe and claim.

- A leading object of the oTIs ALLEN KENroN, or NEW YORK, N. Y.

ELECTRIC WELDING.

. Specification of Letters Patent.

Patented Mar.' 6, 191'?.

Application fileaJune 2s, 1916. serial No. 106,425.

To all whom z't may concern:

Be it known that I, O'rIs ALLEN acitizen of the United States, residing at New York city, in the countyl of New York and State of New York, have invented cer- ,tain new and useful Improvements in Eleci tric Welding, of which the specification.

My invention relates to the ar't of elecfollowing is a tric welding, and it consists of the `partsandthe arrangements and combinations of' parts substantially vas I will hereinafter present .invention is to adjust the current in the arc by means of a; combination of resistances in' such a way, that I may shun't from the main circuit, any desired value of current through 'the-arc without in any way modifying the power and current regulating characteristicsof said arc, which I may adjust to suit the requirements. In other words', in this 'improved system, I use a regulated current welding arc combined. with means adapted to adjust the current through and regulate the power and currentyariations in .said

arc. l

In the. accompanying. Vdrawing forming part of. this specification thefigure illustrates more or less diagrammatically, a cir-- cuit for a system capable of. carrying out 'the present invention. L 'Inorder that the present invention may "be fully understood, andthe value of the same appreciated; I will Vstate that-although electric arc welding is one of" the .oldest practical applications of electricity, it has apparently-not come into the' general vuse 1t .might have, had it been better understood,

and the welding current better controlled. Heretofore, two generalsystems iofelec- Itric distribution have been employed. electric arc welding, namely, the constantpotential system and the constant-current system. The -first-named system, namely,-

y the constant-potential system, is the oldest chine.

and is universally 'used where more than one Welder operates from the same maproperly be' sub-divided ito two types, namely, the open'circuit and the closed. circuit. The open-circuit system-which is well known in the art is limited :to use with one arc on each machine; it has other drawbacks, which I will hereinafter mention.

The closed `circuit constant-current system KENYON,

The constant-current system may was, apparently, first disclosed in my prior Patent No. 1,181,227, dated May 2, 1916, which system has opened -great possibilities In the way of heat control which exist in no other-system of which I have knowledge.

That. the advantages to be derived from the proper control of the heat elects in the welding 'arc may b e better lunderstood, it

is desirable at this time to consider the fac' It yis tors which enter intov said control. known that the rate of total heat production in the arc is equal to the power in watts consumedbetween the terminals ofthe arc, but the temperature of 'the metal is not simply nor directly related tothewatts consumed." In order to control the temperature of the metal, itis necessary then 'to take lnto account all ofthe factorsthat determine it.

Therefore, it maybe well to analyze briefly,l the production of, heat in anelec'tric welding arc.

Beginningl with thepencil point which ordinarily, 'but lnot necessarily, is connected to the negative side lof the'circuit, we ind that the temperature produced' here. .depends upon. the .power in .watts consumed at this point, that is, upon the product of thecurrent through the arc and the E.' M,

F. drop at the terminal of the arc. EX-

perience lhas shown 'that the E. F. dropt at each terminal of. the arc is practically constant, and independent'of 'the current;

that is, .the resistance at each terminal ,of I

the arc .decreases when the. current increases, and vice. versa, which accounts for the` instability of a metallicarc when connected to a source" of constant-potential, and this is the reason why it mustbe connected in series' with 'a relativelylarge resistance.

Therefore, since the E. M. F. is constant,

the temperature of the metal at the pencil point, in' other words, the flow of the metal from the pencil point depends almost enltirely uponthe current alone.

Again, Ithe temperatureof the metal in the arc stream is determined by the power.

of iow from thepencil.

The resistance of. the to be approximately constant per unit of length," so that the E. M.. FL, cons'i'mi'edis directly proportional v'to the length'of the. arc. Thisis the reason that a jcarbon arc with a long stream can be operated from a consumed in the stream, vand :by the rate constant-potential source' with-out la series resistance. The resistance of the arc stream takes the place of an external resistance and stabilizes the arc suliiciently to prevent its being extinguished. The power consumed in the arc is the product of the current through the arc and the voltage drop in the stream; while the flow ofmetal is determined by the'current, as above indicated. Since the resistance of the stream is directly proportional to its length, the length of the arc is fixed by the voltage impressed across it. Therefore, in'order to control the temperature of the metalin the stream, we must control both the current and the E. M. F. and each independently of the other.

The temperature at theend of the. arc

p where it impinges upon the work depends upon the rate of flow of the metal, the temperature of the metal that arrives, and upon .the rate at which energy is produced in the terminal itself, as well as upon the heat.

dissipating capacity of the mass surrounding the point where` the metal 1s deposited.

. I have heretofore considered the origin of the heat brought in by the molten metal itself, and I will here state that the heat produced at this terminal of the arc is exactlyA similar to that produced at the other terminal; that is, it depends upon the current through the arc. Therefore, it will be seen that the final temperature of the metal depends upon both the current and the/E. M. F.; and that the value of each must be controlled independently, if anything like accurate results are to' be obtained While still retaining the flexibility of application.

In the present invention I propose to adjust the current in the arc by means of a lcombination of resistances in such a way that I may shunt from the main circuit, any desired value of current through the arc without in any way modifying the power and current regulating characteristic of the arc which I lnay adjust to suitthe requirements.

In my 'prior Patent No. 1,181,227, dated May 2, 1916, and-in anv application filed of even date herewith, I have disclosed closed circuit constant-current systems which had two 'limitations in the heat adjustment, viz:

(a) The current Awas adjusted by means included in the main circuit and affected all arcs connected in series. Individual adjustment obtained by a shunt across the terminals of the controller (Patent No. 1,181,227 was'not altogether satisfactory from regulation standpoint.

(o) The use of a shunt across the arc prior application referred to) madeit possible to adjust the current for some given voltage, but the constant changing in voltage across the terminal of the arc was accompanied by a variation in current through the arc, that was different for each value of shunt resistance. The present invention provides means for adjusting the current' through the arc without affecting the regulation'characteristic of the shunt around the are.

. To make the invention understood, I will now 'briefly describe the apparatus shown: 1 and 3 are terminals which are connected in a circuit which carries a regulated current; 2 is a short-circuiting contact; 4 is a solenoid coil connected toa separate source, 14, of electricA energy, and which sistance which Iis in series with the contactor, 8; 13 is a shunt; 15 is a 'rheostat of suitable construction, and 24 is an adjustable regulator.

The terminals 1 and 3' are, as before mentioned, connected in a circuit which carries a regulated current.` Normally, the terminals of this circuit areclosed through the shortcircuiting contact, 2, which is heldv closed lby the solenoid coil, 4, connected to the separate source of energ 14.

Connected to the terminals, 1 and 3, I have the resistance, 10, in series with the .Contactor, 8, and the arc-Circuit, 6 and 7, in parallel therewith. The contactor, 8, is also normally closed, but noA current passes that way on account of the fact that the closure at the contact, 2, reduces the voltage drop between the terminals, 1 and 3, to practically nothing.

In operation, the pressing of the'push button, 12, or like circuit closer,shortcir cuits the coil, 4, thereby releasing theA contactor, 2, under the tension of the spring, 16.

Current in the main circuit now passes' portion of the current will immediately pass through the adjustable regulator, 24, the arc, G, and solenoid coil, 7, and in so doing, said' coil, 7, is energized and thereby opens thc contactor, 8, leaving the arc, 6, and the adj ustable shunt, 13, as the only path through -which the main circuit is maintained, and `therefore, carrying all of the current. As

the arc is lengthened and shortened in operation, more or less current is shunted through the part, 13, and solenoid coil, 5. This coil and the-coil, 4, assist each other in pulling against the tension of the spring, 16, and whenever the E. M. F. across the arc,

6, rises suiiiciently it. will force enoughcurrent through the coil, 5, so that the cornbined pull of the coils, 49 and 5, will overcome the tension of the spring, 16, and shortcircuit the arc, by closing the contactor, 2, which prevents' absolutelyany furthertrise in E. M. F. and kills the arc, without any possibility of temperature fiicrease, which will burn the metal. The coil, 4, holds the contactor, 2, closed, killing the arc, 6, and coil, 7 so that the' contactor, -8, is again closed under the action of the spring, 17, leaving the control circuit in exactly the same condition as at the start. The circuit division between the arc, .6, and the shunt, 13, is determined by the adjustment of the regulator or resistance,l24, and any adjustment made in this manner will not affect the percentage change in current through the arc for any given change in voltage. This can only be effected by a change in the resistance of the shun-t, 13. v

It'will be readily seen that the circuits shown are connections of a controller which may be used in a closed circuit-series system, such as described in my prior patent, before alluded to. The shunt in saidpatent was of no use elcept` where more than one arc was used on the circuit. However, in the present instance, the shunt is just as useful in case of one arc alone, as where a series'of arcs are employed. It may also be used on any system to control the regulation characteristic of the arc. j

I, therefore, in the present invention adjust the current in the arc by means of a combination of resistances in such a way that I may shunt from the'main circuit any desired Value of current through the arc without in any way `modifying the power and current regulation characteristic of the arc, which I may adjust to suit the requirements. l

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In electricwelding, a regulated current i Welding arc, means for adjusting .the'cur-V rent through said arc, and additional means for regulating the power and current varia.- tions 1n said arc.

2. In electric Welding, a regulated current welding arc, a shunt circuit around the arc to keep the regulation of the arc current and power Within predetermined limits, and means for adjusting the. current through the arc.

3. In electric Welding, a`regulated current` 4. In electric Welding, a, regulated current Welding arc, and a resistance in- 'series therewith, in combination with a shunt circuit esl around said arcand said resistance, and an adjustable resistance in saidshunt circuit. 

